Toby Lewis, the chief executive of the Sandwell and West Birmingham NHS Trust, confirmed that the construction firm Skanska is their preferred choice to complete the job.

He said: "Our absolute target is to open in 2020 and that is 18 months later than we'd hoped."

The trust now needs the Government to sign off the plan, but the three departments involved have yet to make a decision.

Image:Work on the site in Smethwick has stalled since builders left the site in January

Mr Lewis explained: "I think our time now is for decision and bluntly we can use the summer sunshine to get building.

"We are expecting that to finish this hospital it will cost about £100m to £125m more than had originally been anticipated."

The state-of-the-art facilities will include Europe's biggest emergency department and will also bring much needed regeneration and new homes to Smethwick.

Mr Lewis has been involved in the construction of five other hospitals in his career in the NHS and cannot contemplate not finishing the build.

He said: "What is being jeopardised is the opportunity to offer seven day high quality emergency care.

"We have managed to recruit 130 nurses over the last year that is the sort of thing that is put at risk when we have uncertainty."

Image:Sky News was granted exclusive access to the site which is only two thirds finished

The trust cannot yet confirm the overall costs of the project but previous estimates suggested the build was approximately £350m, with the total cost including the financial agreements closer to £580m.

The mayor of the West Midlands, Andy Street, has written to the Cabinet Office to demand urgent action to prevent further delays and expense.

Mr Street told Sky News: "We really do feel that the next month is the critical time.

"It's really the question of what the delay will be and indeed what the cost will be and that is why I fervently believe that the swifter the decision is made the less the delay will be and the less the cost will be."

Last week a spokesperson for Carillion's official receiver said 10,960 jobs have been saved by workers across their many projects switching to new contractors, but 2,162 jobs have been made redundant through the liquidation.

A spokesperson for the Government said: "The Government is working to minimise the impact and discussions with the trust and PFI company are ongoing to ensure there are plans in place to keep any construction delays to a minimum."